Reformer to pardon gangster after turnaround (7)
I believe the answer is:
latimer
'reformer' is the definition.
(Hugh Latimer, 16th-century reformer)
'pardon gangster after turnaround' is the wordplay.
'pardon' becomes 'remit' (I've seen this in another clue).
'gangster' becomes 'al' (Al Capone).
'after' means one lot of letters go next to another.
'turnaround' shows that the letters should be reversed in order.
'remit'+'al'='remital'
'remital' reversed gives 'LATIMER'.
'to' is the link.
(Other definitions for latimer that I've seen before include "old bishop" , "The church burned this bishop" , "One burnt with Ridley at Oxford" , "One of the Oxford Martyrs" , "Bishop condemned" .)